微生物および生化学技術ジャーナル

概要

Battling the Methicillin-Resistant Staphylococcus aureus Biofilm Challenge with Vancoplus

Manu Chaudhary and Anurag Payasi

The present study was conducted with the aim to find the prevalence of biofilm formation ability among methicillin resistant Staphylococcus aureus (MRSA) isolates and to assess the activities of commonly used drugs against biofilm producing MRSA. Evaluation of prevalence of genes involved in MRSA biofilm production and their gene expression was also studied. Of 55 MRSA, 47 isolates were biofilm producers and 8 isolates were non-biofilm producers. Of 47 biofilm producers, 24 (51.0%), 14 (29.8%) and 9 (19.1%) produced strong (OD570 ≥ 0.5), medium (OD570 ≥ 0.2 to <0.5), weak (OD570 0 to <0.2) biofilm, respectively. Of the 47 isolates, eight determinants (genes) (eno, hla, hlb, clfA, fnaA, icaA, agrII and sar) were found predominantly among 70 to 80% isolates whereas cna was observed only in 21.3%, finbB in 10.6% and ebps in 32% isolates. Amongst the strong biofilm producers (51%), the lowest MIC values obtained with Vancoplus (2-4 μg/ml) >linezolid (128 to 256 μg/ml) >daptomycin, clindamycin and teicoplanin (256 to 512 μg/ml). Biofilms eradication rate was also observed in the same order with Vancoplus (87%) >linezolid (51.8%) >clindamycin (31.9%) >daptomycin (27.5%) >teicoplanin (26.5%). Our results showed that the percentage of finbA, hla, eno, clfA and fib genes expressions down-regulation after Vancoplus treatment was 64.0 ± 5.9, 63.8 ± 5.8, 73.0 ± 7.4, 72.8 ± 7.8 and 71.9 ± 7.8%, respectively as compared to the control among strong biofilm producing MRSA whereas teicoplanin produced only 30.3 ± 2.7 to 34.5 ± 3.8% down regulation in fnbA, hla, eno, clfA and fib genes expression. The other comparator drugs, vancomycin, linezolid and daptomycin, demonstrated variable effects on these genes varying from 4.9 ± 3.9 to 30.3 ± 2.7%. Our data showed that Vancoplus has significantly enhanced activity against MRSA biofilm producing isolates as compared to other drugs. Therefore, use of this antibiotic should be considered to treat the infections caused by biofilm producing MRSA.